Mr. and Mrs. Karan Johar is the story of a happily married couple…
or so until, Mrs. Johar i.e Khushbu Johar doubts the fidelity of her
husband for reasons best known to her. This doubt reaches its peak
when Karan, for some reason, doesn't come home one night but
reaches the next day, early in the morning.

Her doubts are even more ascertained when she finds a diamond
necklace in the pocket of Karan's coat. Each and every time Karan
was interrogated for it, his next door neighbor, Harry who he thought
was his savior steps in and leaves him extremely worked up or until
Karan feel like he is in hell.

What adds fuel to the fire is the entry of Chandni from 'Chandni Bar'
who comes to take her diamond necklace back. Unfortunately, by that
time Khushbu leaves the house to go to her mother's house taking
the diamond necklace along with her.

Chandni tells Karan that she needs the diamond necklace back as it
didn't belong to her but some sharp shooter by the name of Shetty,
who gave it to her on a particular outing.

Then begins the cat and mouse chase to get the necklace back from
Khushbu and secondly, to make her realize that it did not belong
to her. Lastly, to prove to the surveyor of the insurance company
that Karan was, actually and truly, badly hurt in a bus accident.
Everything leads to a big build up of lies, causing a laugh riot among
the audience, until it renders Karan helpless.